rt_thread_yield的修改，不知道是否更优

发布于 2012-08-18 12:50:19 浏览：2964 订阅该版

RTT的调度是时间片到了将当前任务放到队尾（先从对头删除，再插入队尾），然后继续使用队列头作为to。
听了默存的指点，说可以不删除和插入操作，直接取当前任务的next就可以了。于是我看了代码后做出以下改动，还请各位丢砖。 [s:188] 
```rt_err_t rt_thread_yield(void)
{
	register rt_base_t level;
	struct rt_thread *thread;

/* disable interrupt */
	level = rt_hw_interrupt_disable();

/* set to current thread */
	thread = rt_current_thread;

/* if the thread stat is READY and on ready queue list */
	if (thread->stat == RT_THREAD_READY && thread->tlist.next != thread->tlist.prev)
	{
#if 0
		/* remove thread from thread list */
		rt_list_remove(&(thread->tlist));

/* put thread to end of ready queue */
		rt_list_insert_before(&(rt_thread_priority_table[thread->current_priority]),
			&(thread->tlist));

/* enable interrupt */
		rt_hw_interrupt_enable(level);

rt_schedule();
#else
		if (thread->tlist.next != &(rt_thread_priority_table[thread->current_priority]))
		{
			rt_current_thread = rt_list_entry(rt_thread_priority_table[thread->current_priority].next,
						struct rt_thread, tlist);
		}
		else
		{
			rt_current_thread = rt_list_entry(rt_thread_priority_table[thread->current_priority].next->next,
						struct rt_thread, tlist);
		}
		
		if (rt_interrupt_nest == 0)
		{
			rt_hw_context_switch((rt_uint32_t)&thread->sp, (rt_uint32_t)&rt_current_thread->sp);
		}
		else
		{
			RT_DEBUG_LOG(RT_DEBUG_SCHEDULER, ("switch in interrupt
"));

rt_hw_context_switch_interrupt((rt_uint32_t)&thread->sp, (rt_uint32_t)&rt_current_thread->sp);
		}
		
		/* enable interrupt */
		rt_hw_interrupt_enable(level);
#endif
		return RT_EOK;
	}

/* enable interrupt */
	rt_hw_interrupt_enable(level);

return RT_EOK;
}```